We did this removal of the Air Conditioning on our own Cosworth Supercharged 2007 about a year ago to remove weight from the front end. Got a request to post the notes. Here they are. The key to this is that Mazda/Ford already makes an Idler/Pulley replacement for this block which is the "New Pulley" in diagram below. LF17-15-940E is the current part number. Pretty sure that I got said new pulley from Mazda Comp, it is a standard part for the markets that have no A/C and goes on the block in place of the compressor (used in markets that don't need A/C like Canada, etc). Perhaps the next person to do this job can expand on the notes here by adding that part number.
2015 Update (For 2.5 Liter Customers see THIS THREAD).